[1.2.X] Fixed #13790 -- auto detection of m2m fields to Site. Thanks, gabrielhurley!

class CurrentSiteManager(models.Manager):

    "Use this to limit objects to those associated with the current site."

    def __init__(self, field_name='site'):

    def __init__(self, field_name=None):

        super(CurrentSiteManager, self).__init__()

        self.__field_name = field_name

        self.__is_validated = False

    def get_query_set(self):

        if not self.__is_validated:

    def _validate_field_name(self):

        field_names = self.model._meta.get_all_field_names()

        # If a custom name is provided, make sure the field exists on the model

        if self.__field_name is not None and self.__field_name not in field_names:

            raise ValueError("%s couldn't find a field named %s in %s." % \

                (self.__class__.__name__, self.__field_name, self.model._meta.object_name))

        # Otherwise, see if there is a field called either 'site' or 'sites'

        else:

            for potential_name in ['site', 'sites']:

                if potential_name in field_names:

                    self.__field_name = potential_name

                    self.__is_validated = True

                    break

        # Now do a type check on the field (FK or M2M only)

        try:

                self.model._meta.get_field(self.__field_name)

            field = self.model._meta.get_field(self.__field_name)

            if not isinstance(field, (models.ForeignKey, models.ManyToManyField)):

                raise TypeError("%s must be a ForeignKey or ManyToManyField." %self.__field_name)

        except FieldDoesNotExist:

            raise ValueError("%s couldn't find a field named %s in %s." % \

                    (self.__class__.__name__, self.__field_name, self.model._meta.object_name))

        self.__is_validated = True

    def get_query_set(self):

        if not self.__is_validated:

            self._validate_field_name()

        return super(CurrentSiteManager, self).get_query_set().filter(**{self.__field_name + '__id__exact': settings.SITE_ID})

from django.contrib.sites.managers import CurrentSiteManager

from django.contrib.sites.models import Site

from django.db import models

class AbstractArticle(models.Model):

    title = models.CharField(max_length=50)

    objects = models.Manager()

    on_site = CurrentSiteManager()

    class Meta:

        abstract = True

    def __unicode__(self):

        return self.title

class SyndicatedArticle(AbstractArticle):

    sites = models.ManyToManyField(Site)

class ExclusiveArticle(AbstractArticle):

    site = models.ForeignKey(Site)

class CustomArticle(AbstractArticle):

    places_this_article_should_appear = models.ForeignKey(Site)

    objects = models.Manager()

    on_site = CurrentSiteManager("places_this_article_should_appear")

class InvalidArticle(AbstractArticle):

    site = models.ForeignKey(Site)

    objects = models.Manager()

    on_site = CurrentSiteManager("places_this_article_should_appear")

class ConfusedArticle(AbstractArticle):

    site = models.IntegerField()

from django.conf import settings

from django.contrib.sites.models import Site

from django.test import TestCase

from models import SyndicatedArticle, ExclusiveArticle, CustomArticle, InvalidArticle, ConfusedArticle

class SitesFrameworkTestCase(TestCase):

    def setUp(self):

        Site.objects.get_or_create(id=settings.SITE_ID, domain="example.com", name="example.com")

        Site.objects.create(id=settings.SITE_ID+1, domain="example2.com", name="example2.com")

    def test_site_fk(self):

        article = ExclusiveArticle.objects.create(title="Breaking News!", site_id=settings.SITE_ID)

        self.assertEqual(ExclusiveArticle.on_site.all().get(), article)

    def test_sites_m2m(self):

        article = SyndicatedArticle.objects.create(title="Fresh News!")

        article.sites.add(Site.objects.get(id=settings.SITE_ID))

        article.sites.add(Site.objects.get(id=settings.SITE_ID+1))

        article2 = SyndicatedArticle.objects.create(title="More News!")

        article2.sites.add(Site.objects.get(id=settings.SITE_ID+1))

        self.assertEqual(SyndicatedArticle.on_site.all().get(), article)

    def test_custom_named_field(self):

        article = CustomArticle.objects.create(title="Tantalizing News!", places_this_article_should_appear_id=settings.SITE_ID)

        self.assertEqual(CustomArticle.on_site.all().get(), article)

    def test_invalid_name(self):

        article = InvalidArticle.objects.create(title="Bad News!", site_id=settings.SITE_ID)

        self.assertRaises(ValueError, InvalidArticle.on_site.all)

    def test_invalid_field_type(self):

        article = ConfusedArticle.objects.create(title="More Bad News!", site=settings.SITE_ID)

        self.assertRaises(TypeError, ConfusedArticle.on_site.all)